Currently, various steel-made utensils are used in medical field. “steel-made utensil” means an instrument for operations made of metal such as stainless steel. Steel-made utensils include tweezers, needle holders, scalpels, scissors, forceps, wound retractors, chisels, cupped forceps and the like. Kinds of such steel-made utensils amount to approximately 30, and there are several hundred variations in shapes of distal ends and sizes of these steel-made utensils. Being made of metal, these steel-made utensils have advantages and disadvantages.
For example, as one of steel-made wound retractors, to facilitate the viewing of the center of field of operation, there has been used an instrument called a retractor which retracts a peripheral tissue by hooking by a hook-shaped portion formed on a distal end of the retractor. With respect to this metal-made retractor, patent document 1 points out various drawbacks.
That is, as the drawbacks of a metal-made retractor, the following drawbacks are pointed out. A metal-made retractor is heavy and hence, a large burden is placed on a user's hand. A metal-made retractor is heavy and hence, a large-sized metal-made retractor cannot be manufactured. A flash of light is generated under high level illumination due to reflection of the light. Since a metal-made retractor has high thermal conductivity, the metal-made retractor rapidly absorbs heat from a tissue of an affected part thus giving rise to a possibility that the patient suffers from a heat shock. Since metal-made retractors are expensive, the inventory of retractors at facilities in a hospital is liable to be constantly insufficient.
To overcome such drawbacks which a steel-made utensil has, patent document 1 proposes a retractor for operations which includes constitutional elements consisting of: an integrally-formed blade which has a non-reflective surface and is made of an elastic and strong plastic material; a grip; and a shank which connects the grip and the blade to each other.
Further, as drawbacks in medical field, patent document 2 points out drawbacks brought about by a shortage of illumination, a shortage of reflection or the like in a field of operation.
To overcome the drawbacks relating to the illumination, patent document 2 proposes a medical wound retractor illumination system where a light source is mounted on a removable handle portion of a wound retractor, and light incident through an incident port formed in a portion of the wound retractor near the handle is emitted toward a field of operation existing near a blade portion remote from the handle through a light guide in the wound retractor.
[Patent document 1] Japanese Examined Patent Application Publication No. 48-3440
[Patent document 2] Japanese Translation of PCT International Publication No. JP-T-2009-523551